File storage cabinets are used for filing documents and are generally of the vertical and lateral type. Such file cabinets usually include a number of file drawers vertically stacked with each file drawer being movable from within the cabinet housing to an extended open position to provide access to the drawer space. In a vertical file cabinet the length of the file drawer extends out of the file cabinet housing with the files extending across the drawer, whereas in a lateral file drawer the length of the drawer extends across the cabinet housing so that when the drawer is opened it is moved transverse to its length.
It very frequently occurs that if more than one drawer is moved to the open position at the same time, the file cabinet assembly has a tendency to tip forward in the opening direction of the drawers. In such cabinets which only allow one drawer to open, installation of the drawers within the cabinets is often difficult and requires manual intervention controlling the locking assembly. Many of these systems include mechanisms disposed along one side of the drawers for being moved to a locking position in response to opening movement of one of the drawers. Additionally, there are occasions in which the locking means when opened will disengage and require re-installation of the drawer by manually moving the locking means to properly engage the drawer when in the opened position.
U.S. Pat. No. 3,454,320 to Olree discloses a system having a rod with a radially extending actuating arm associated with each drawer for rotating the rod upon opening movement of the drawer to rotate a second locking arm associated therewith into interfering position with each of the other drawers. The actuating arm includes a sloping edge on the abutment means acting as a cam in raising the arm to allow the drawer to move into its closed position when the drawer is open and the locking arm closed. Only one drawer is allowed to move against the finger element to the closed position at a time. A major deficiency in this system is that it allows two drawers to rotate the rod simultaneously during opening movement of both drawers, and only one drawer to be installed at a time.
Another such assembly is disclosed in German patent DE 3431386 Al published Mar. 6, 1986 in the name of Anton Kessel. The patent discloses a stack of tubular members and tubular gears telescoped unto an inner tube with the bottom tubular member bottomed out or not movable vertically. Upon rotation of any one of the gears, only the stack above the rotated gear moves vertically upward as the stack below remains vertically fixed as the force reaction occurs at the bottom of the stack. This also requires manual intervention of rotating the gear in the open position in order to install the drawers.
My previous assembly includes vertically stacked elements which are vertically movable to drawer-locking positions in response to opening movement of one of the drawers. This assembly is disclosed in U.S. patent application Ser. No. 058,028, filed June 4, 1987, now U.S. Pat. No. 4,772078, and assigned to the assignee of this invention. The application discloses a housing having control means vertically disposed along side of each vertically stacked drawer. The control means includes a pinion gear having teeth about its circumference coacting with the drawer for rotating as the drawer is moved toward open to move blocking means of all other drawers to their blocking positions allowing only a single drawer to be opened at a time. The stack of blocking means above the rotated pinion moves vertically upward from a neutral position while the stack below the rotated pinion moves vertically downward from the neutral position. In order to initially install a drawer in the housing, the pinion must be moved to its actuated or open position for engagement with the drawer in its open position. Additionally, there are occasions when the pinion will rotate back to its neutral position while the drawer remains open; this requires manual intervention to rotate the pinion back to its actuated or open position in order to close the drawer.